Liquid crystal composition and liquid crystal device

Abstract

The disclosure provides a liquid crystal device including a liquid crystal composition containing a dichroic dye (dye-containing liquid crystal composition) that is in a light transmissive state when no voltage is applied to the transparent electrode and in a light scattering state when voltage is applied. The liquid crystal composition exhibits a negative dielectric constant anisotropy. The haze value of the liquid crystal device is 10% or less when no voltage is applied at 25° C., and the haze value is 50% or more when a rectangular wave voltage (AC 50 V, 60 Hz) is applied. The voltage holding ratio of the dye-containing liquid crystal composition is 60% or less at 25° C. The liquid crystal device provided by the disclosure is used as a component to provide a liquid crystal display apparatus, a light control apparatus, or a light transmitting apparatus with a high contrast.

What is claimed is: 
     
         1 . A liquid crystal device comprising:
 two transparent substrates, at least one of the transparent substrates having a transparent electrode; and   a drive layer containing a liquid crystal composition containing a dichroic dye (dye-containing liquid crystal composition) disposed between the transparent substrates,   the liquid crystal device being in a light transmissive state when no voltage is applied to the transparent electrode and being in a light scattering state when voltage is applied, wherein   the liquid crystal composition exhibits a negative dielectric constant anisotropy,   a haze value of the liquid crystal device is 10% or less when no voltage is applied at 25° C., and the haze value is 50% or more when a rectangular wave voltage (AC 50 V, 60 Hz) is applied, and   a voltage holding ratio of the dye-containing liquid crystal composition (the liquid crystal composition is injected into a cell with a cell thickness of 10 μm, 10 V is applied with a pulse width of 60 μs, and a ratio between a measurement voltage measured after a frame time of 16.7 ms and an initial applied voltage is expressed by % as the voltage holding ratio) is 60% or less at 25° C.   
     
     
         2 . The liquid crystal device according to  claim 1 , wherein the drive layer does not contain a polymer network. 
     
     
         3 . The liquid crystal device according to  claim 1 , wherein a vertical alignment film is installed on a surface of the transparent substrate in contact with the drive layer. 
     
     
         4 . The liquid crystal device according to  claim 1 , wherein the dichroic dye is a compound represented by general formula (1) 
       
         
           
           
               
               
           
         
         (wherein U is one group selected from groups represented by general formulae (2) to (5) 
       
       
         
           
           
               
               
           
         
         
           R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , and R 9  each independently represent a hydrogen atom, a fluorine atom, a cyano group, an alkyl group having 1 to 20 carbon atoms, or an alkenyl group having 2 to 30 carbon atoms, one —CH 2 — or two or more nonadjacent —CH 2 —'s present in these groups are optionally substituted with —NR N1 —, —O—, —S—, —CO—, —CS—, —COO—, —OCO—, —CO—S—, —S—CO—, —SO—, —SO 2 —, —O—CO—O—, —CO—NH—, —NH—CO—, —CH═CH—, —CF═CF—, or —C≡C—, a hydrogen atom present in these groups is optionally substituted with a fluorine atom, wherein R N1  represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkenyl group having 2 to 30 carbon atoms, one —CH 2 — or two or more nonadjacent —CH 2 —'s present in these groups are optionally substituted with —O—, —S—, —COO—, —OCO—, or —CO—, and a hydrogen atom present in these groups is optionally substituted with a fluorine atom, 
           R a , R b , and R c  each independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkenyl group having 2 to 30 carbon atoms, one —CH 2 — or two or more nonadjacent —CH 2 —'s present in these groups are optionally substituted with —NR N2 —, —O—, —S—, —CO—, —CS—, —COO—, —OCO—, —CO—S—, —S—CO—, —SO—, —SO 2 —, —O—CO—O—, —CO—NH—, —NH—CO—, —CH═CH—, —CF═CF—, or —C≡C—, a hydrogen atom present in these groups is optionally substituted with a fluorine atom, wherein R N2  represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkenyl group having 2 to 30 carbon atoms, one —CH 2 — or two or more nonadjacent —CH 2 —'s present in these groups are optionally substituted with —O—, —S—, —COO—, —OCO—, or —CO—, a hydrogen atom present in these groups is optionally substituted with a fluorine atom, 
           X a , X b , X c , X d , and X e  each independently represent —S— or —O—, 
           A 1 , A 2 , A 4 , A 5 , A a , A b , A d1 , A d2 , A e1  and A e2  each independently represent an optionally substituted hydrocarbon ring or heterocyclic ring having 3 to 16 carbon atoms, 
         
         Z 1 , Z 2 , Z 4 , Z 5 , Z a , Z b , Z c , Z d1 , Z d2 , Z e1 , and Z e2  each independently represent —CH 2 O—, —OCH 2 —, —CF 2 O—, —OCF 2 —, —COO—, —OCO—, —CH 2 CH 2 —, —CF 2 CF 2 —, —CH═CH—, —CF═CF—, —N═CH—, —CH═N—, —N═N—, —C≡C—, or a single bond,
 i, j, a, b, c, d, e, f, g, and h each independently represent an integer of 0 to 4, and 
 pluralities of A 1 s, A 2 s, A 4 s, A 5 s, A a s, A b s, A d1 s, A d2 s, A e1 s, and A e2 s, if present, may be the same or different A 1 s, A 2 s, A 4 s, A 5 s, A a s, A b s, A d1 s, A d2 s, A e1 s, and A e2 s, pluralities of Z 1 s, Z 2 s, Z 4 s, Z 5 s, Z a s, Z b s, Z c s, Z d1 s, Z d2 s, Z e1 s, and Z e2 s, if present, may be the same or different Z 1 s, Z 2 s, Z 4 s, Z 5 s, Z a s, Z b s, Z c s, Z d1 s, Z d2 s, Z e1 s, and Z e2 s, and pluralities of R N1 s and R N2 s, if present, may be the same or different R N1 s and R N2 s). 
 
       
     
     
         5 . The liquid crystal device according to  claim 1 , wherein the dye-containing liquid crystal composition further contains a haze adjuster. 
     
     
         6 . The liquid crystal device according to  claim 1 , wherein the dye-containing liquid crystal composition contains one or two or more compounds represented by general formula (II) 
       
         
           
           
               
               
           
         
         (wherein
 R II1  represents an alkyl group having 1 to 10 carbon atoms, one or two or more nonadjacent —CH 2 —'s in the alkyl group are each independently optionally substituted with —CH═CH—, —O—, —CO—, —COO—, or —OCO—, 
 A II1  and A II2  each independently represent a group selected from the group consisting of 
 
         (a) a 1,4-cyclohexylene group (in which one —CH 2 — or two or more nonadjacent —CH 2 —'s are optionally substituted with —O—), 
         (b) a 1,4-phenylene group (in which one —CH═ or two or more nonadjacent —CH═'s are optionally substituted with —N═), and 
         (c) a naphthalene-2,6-diyl group, a 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, or a decahydronaphthalene-2,6-diyl group (one —CH═ or two or more nonadjacent —CH═'s present in the naphthalene-2,6-diyl group or the 1,2,3,4-tetrahydronaphthalene-2,6-diyl group are optionally substituted with —N═),
 the group (a), the group (b), and the group (c) are each independently optionally substituted with a cyano group, a fluorine atom, or a chlorine atom, 
 Z II1  represents a single bond, —CH 2 CH 2 —, —(CH 2 ) 4 —, —OCH 2 —, —CH 2 O—, —COO—, —OCO—, —OCF 2 —, —CF 2 O—, —CH═N—N═CH—, —CH═CH—, —CF═CF—, or —C≡C—, 
 Y II1  represents a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group, or an alkyl group having 1 to 10 carbon atoms, one or two or more nonadjacent —CH 2 —'s in the alkyl group are each independently optionally substituted with —CH═CH—, —O—, —CO—, —COO—, or —OCO—, and one or two or more hydrogen atoms in the alkyl group are optionally substituted with a fluorine atom, and 
 m II1  represents 1, 2, 3, or 4, wherein when m II1  represents 2, 3, or 4, a plurality of A II1 s and a plurality of Z II1 s are optionally same or different). 
 
       
     
     
         7 . The liquid crystal device according to  claim 1 , wherein a maximum absorption wavelength of the dichroic dye is 600 nm or more and 750 nm or less. 
     
     
         8 . The liquid crystal device according to  claim 1 , wherein the dye-containing liquid crystal composition contains two or more dichroic dyes. 
     
     
         9 . The liquid crystal device according to  claim 1 , wherein the liquid crystal device is driven by a rectangular wave having a frequency of 30 to 300 Hz. 
     
     
         10 . A liquid crystal display apparatus, a light control apparatus, or a light transmitting apparatus comprising the liquid crystal device according to  claim 1 .